In general, a gyro compass causes the gyro rotor to precess depending on the rate of the Earth's rotation to seek the north. In its normal operation precession is produced depending on a vector component of the rate of the Earth's rotation about the true vertical and the other vector component of the rate of the Earth's rotation about the north/south horizontal at a latitude on the Earth's surface to stably point the spin axis of the rotor to the north.
However, if the spin axis of the rotor is deviated from the north, or the inclination angle of the spin axis of the rotor with respect to the Earth's surface is departed from an inclination angle thereof in the equilibrium state when the gyro compass is started to be driven, precession is caused to be produced due to a vector component of the rate of the Earth's rotation about the north/south horizontal and the other vector component of the rate of the Earth's rotation about the true vertical so that the north seeking end of the axis of the rotor draws an elliptical trace and is brought to point an equilibrium direction a long time after the compass is started. During a time period from an instant at which the gyro compass is started to another instant at which it is brought to an equilibrium state, a bearing can not be measured precisely. Accordingly, this time period for stabilization should be made as short as possible.